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Finding the Fourth Proportional to 121.57, 181.91 and 72.85

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Solution

The fourth proportional to 121.57, 181.91 and 72.85 is: 109.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    121.57 : 181.91 = 72.85 : x
  2. Step 2: Convert to fraction form
    121.57/181.91 = 72.85/x
  3. Step 3: Cross multiply
    121.57x = 181.91 × 72.85
  4. Step 4: Simplify right side
    121.57x = 13,252.14
  5. Step 5: Solve for x
    x = 13,252.14/121.57
  6. Step 6: Final answer
    x = 109.01

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.